<!DOCTYPE html> 
<html lang="en"> 
<head> 
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width,initial-scale=1.0" charset="UTF-8" />
    <title>任务管理器监控内存变化</title> 
</head> 
<body>
    <button id="btn">
        Add
    </button>
<script type="text/javascript">
    var tmpEle

    function  fn() {
        var ul = document.createElement('ul')
        for(var i = 0; i<10 ;i++ ){
            var li = document.createElement('li')
            ul.appendChild(li)
        }
        tmpEle = ul
    }

    document.getElementById('btn').addEventListener('click',fn)//js中创建的节点并没有往我们页面里添加，是分离的DOM
</script> 
</body> 
</html>